Tech. Fishtales Power driver board no 5volts Options

[Maxprofits]

I can't get the 5v cct on my fishtales to work. I have replaced all
the 15000uf 25V electrolitic caps, BR1, LM323 (the 5v reg), checked
that D3 and D38 are good, confirmed that I have 9.8VAC in between pins
1 and 2 on J101. Fuse 13 is good (tested out of circuit). TP 2 in 0V (should be 5VDC)
LED's 2,3 and 4 are off. The 12VDC and 20Vdc are good. The 50VDC- TP6
is high 75VDC. About the only thing I have not replaced is the LM339
comparitor and C9 tantalum. The fuse values are correct and the board
does not blow fuses. All caps are installed the correct way.
Any ideas?
I'm really scratching my head on this one.

[dj10555]

Have you tried measuring the 5v without any other boards being connected (which could be loading it down.) Do you have a voltage on the input side of the LM323?
I have seen a few tantalums go short before but this would probably blow the fuse.  Pinrepair.com mentions that the tracks leading/from to BR2 can easily be broken so you could check the continunity of these. I also had a regulator go faulty a few nights ago where I could put a small load (100mA) across it it would measure fine but if I put a 2A load across it it just shut down.  Hope these give you a few ideas.
regards Derek

[Maxprofits]

Thanks for the ideas, I will try these out tomorrow, when I'm sober.
regards,
Dan

[Pinball Fixers]

You mention BR1 as the bridge you replaced... this should be BR2. If you haven't replaced BR2, then make sure to do so.

0V at TP2 usually indicates an open-circuited part, blown fuse, or a broken trace, so you'll need to follow the voltage path through from J101. Make sure that you have connection between the bridge, cap and regulator, as these are the most common places to have a break (usually the cap).

I would doubt that you have another board pulling the voltage down at this stage (but it could be the problem).

[Maxprofits]

Turns out that the through hole plating was missing on the positive side of C5, hard to find as the solder pads looked good. Anyhow got it fixed now thanks to the advice, it got me looking the right place again. Now to find out why the Dot matrix controller board stops the machine from booting up.

thanks,
Dan